1. Field of the Invention
The present invention relates to a method for managing a network in which Bluetooth equipped devices are linked together, and more particularly, to a method for managing a network by a backup master when the master of the network cannot serve as a master in the network operating region. The present application is based on Korean Patent Application No. 2000-42866, which is incorporated herein by reference.
2. Description of the Related Art
Bluetooth technology relates to a wireless communications method having no centralized control function, in which wireless transmission and reception of data between Bluetooth equipped devices are established in a local area, without cables. Although one-to-one or one-to-multi connection can be established, due to the lack of the centralized control function, the Bluetooth technology has not been applied in a network. To manage Bluetooth equipped devices in a network, one of the Bluetooth equipped devices must be designated as a master of the network, i.e., the Bluetooth piconet.
Referring to FIGS. 1 and 2, in a conventional method for designating a master and slaves in a network in which a plurality of Bluetooth equipped devices are linked together, when power is applied to a Bluetooth equipped device, a network manager 160 of the Bluetooth equipped device inquires as to whether any Bluetooth equipped device exists within a radio coverage region (S212). The network manager 160 determines whether the response from any Bluetooth equipped device is detected (S214). The network manager 160 of the Bluetooth equipped device, to which power is applied, serves as the master or a slave of the network according to whether there is a response or not in step S214. In particular, if there is no response to the inquiry in step S214, the network manager 160 sets a master mode, and performs inquiry scan (S216) and page scan (S218). The network manager 160 chosen as the network master checks whether any Bluetooth equipped device attempts to establish a connection (S220). If yes, the network manager 160 accepts the request for connection, and requests the Bluetooth equipped device, which requests connection, to change its role to a slave, while the network manager 160 remains as the master of the network (S222). Then, the network manager 160 transfers information on itself, as the network master, and information on other slaves, to the new slave linked to the network. The network manager 160 also stores information on new slaves or the slaves which have left the network, such as addresses or names of the slaves, and announces the stored information to the other slaves linked to each other throughout the network (S224).
Meanwhile, in step S220, if there is no connection request from any Bluetooth equipped device, a determination as to whether to change the mode is made (step S226). The mode can be changed when a user wants to modify a role of the Bluetooth equipped device from the master to a slave, when the Bluetooth function is switched off, or when power is turned off. If it is determined in step S226 to keep the master mode, the process returns to step S216 to continue its role as the network master. In contrast, if it is determined in step 226 to change the mode, the master mode is expired.
Meanwhile, in step S214, if a response to the inquiry is detected in step S214, this means that a preexisting network exists within the radio coverage region. In this case, in order to enter the preexisting Network, the network manager 160 pages the master of the preexisting Network to establish a connection (S232). If the connection is established, the network manager 160 changes its role to a slave with respect to the master of the preexisting network (S234). Next, the network manager 160 receives information on the other slaves of the preexisting network from the network master (S236), thereby terminating the designation of master or slave in the network. After the role of the Bluetooth equipped device is designated as a slave, and when the slave does not communicate with other Bluetooth equipped devices, the mode is changed to a park mode. In the park mode, the slave receives information from the new network master to update its old network information. In contrast, if the Bluetooth equipped device, a new slave NS, whose role is changed as a slave attempts to communicate with another slave within the network, the new slave NS requests the network master to cut off the connection with the corresponding slave CS, communicates with the corresponding slave CS, and then cuts off the connection with the corresponding slave CS in order to return into the network.
As described previously, the Bluetooth equipped device can serve as the master or a slave in the network depending on the response to the inquiry. The network consisting of Bluetooth equipped devices allows entering of new Bluetooth equipped devices into the network, sharing information with other Bluetooth equipped devices in the network, and communication among any Bluetooth equipped device of the network in response to a request of any of the Bluetooth equipped devices.
However, there is a need for designating a new master or reconfiguring the network when the network master cannot serve as a master at a point of time, for example, when power is exhausted or the master leaves the network operating region.